GCN Circular 12983
Subject
GRB 120224A: Swift-BAT refined analysis
Date
2012-02-24T13:26:41Z (12 years ago)
From
Scott Barthelmy at NASA/GSFC <scott@lheamail.gsfc.nasa.gov>
S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC), J. R. Cummings (GSFC/UMBC),
E. E. Fenimore (LANL), N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA),
C. B. Markwardt (GSFC), D. M. Palmer (LANL), T. Sakamoto (GSFC/UMBC),
G. Sato (ISAS), C. J. Saxton (UCL-MSSL), M. Stamatikos (OSU),
J. Tueller (GSFC), T. N. Ukwatta (MSU)
(i.e. the Swift-BAT team):
Using the data set from T-239 to T+326 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 120224A (trigger #515976)
(Saxton, et al., GCN Circ. 12980). The BAT ground-calculated position is
RA, Dec = 40.937, -17.779 deg, which is
RA(J2000) = 02h 43m 44.8s
Dec(J2000) = -17d 46' 42.6"
with an uncertainty of 2.4 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 29%.
The mask-weighted light curve shows two peaks, the first starting
at ~T-20 sec, peaking at ~T-6 sec. The second (and stronger peak)
starts at ~T-3 sec, peaks at ~T+1 sec, and ends at ~T+13 sec.
T90 (15-350 keV) is 8.13 +- 1.99 sec (estimated error including systematics).
The time-averaged spectrum from T-1.08 to T+8.26 sec is best fit by a simple
power-law model. The power law index of the time-averaged spectrum is
2.25 +- 0.36. The fluence in the 15-150 keV band is 2.4 +- 0.5 x 10^-7 erg/cm2.
The 1-sec peak photon flux measured from T+0.24 sec in the 15-150 keV band
is 0.9 +- 0.2 ph/cm2/sec. All the quoted errors are at the 90% confidence
level.
The results of the batgrbproduct analysis are available at
http://gcn.gsfc.nasa.gov/notices_s/515976/BA/